Infection Dynamics of Centrocestus armatus Cercariae (Digenea: Heterophyidae) to Second Intermediate Fish Hosts

• Published in: The Journal of parasitology 2007-04, Vol.93 (2), p.436-439
• Main Authors: Paller, V. G V, Kimura, D, Uga, S
• Format: Article
• Language: English
• Subjects: Age; Animals; Biological and medical sciences; Centrocestus; Centrocestus armatus; Cercaria; Cercariae; Cyprinidae - parasitology; Data transmission; Density; Digenea; Disease transmission; Fish; Fish Diseases - parasitology; Fish Diseases - transmission; Fish scales; Frequency dependence; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Heterophyidae; Host-Parasite Interactions; Infections; Infectivity; Invertebrates; Linear Models; Models, Biological; Mollusks; Mortality; Nemathelminthia. Plathelmintha; Parasite hosts; Parasites; Parasitology; Population Density; Regression analysis; RESEARCH NOTES; Semisulcospira libertina; Snails - parasitology; Survival; Survival Rate; Time Factors; Trematoda - physiology; Trematode Infections - parasitology; Trematode Infections - transmission; Trematode Infections - veterinary
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/GE-997R.1

The infection dynamics of Centrocestus armatus cercariae with respect to second intermediate fish hosts were investigated using cercariae collected from naturally infected Semisulcospira libertina. Cercariae survival and infectivity were recorded at 2-hr intervals. Survival remained constant but decreased abruptly at 30 hr of age. An age-dependent model presented the best-fit curve for the survival data (r2 = 0.936), implying that cercariae tended to allocate resources equally among themselves and then died once those resources were depleted. Cercariae infectivity remained constant over the first 10 hr of life and then declined; an age-dependent model also provided a better fit (r2 = 0.956). The transmission rate of C. armatus cercariae to the fish host was relatively low near the time of emergence from the snail host but peaked at 85% after 1 hr and then maintained a plateau period until 5 hr of exposure to fish. The pattern of transmission was also investigated initially at varying densities of cercariae and then by maintaining a constant cercariae density but varying the total number. Results revealed that the pattern of transmission was frequency-dependent.